Matt Richtel's NY Times article on The Lure of Data is interesting from the always on aspect, but it's also interesting for the multitasking aspect.

The pair have their own term for this condition: pseudo-attention deficit disorder. Its sufferers do not have actual A.D.D., but, influenced by technology and the pace of modern life, have developed shorter attention spans. They become frustrated with long-term projects, thrive on the stress of constant fixes of information, and physically crave the bursts of stimulation from checking e-mail or voice mail or answering the phone.

"It's like a dopamine squirt to be connected," said Dr. Ratey, who compares the sensations created by constantly being wired to those of narcotics - a hit of pleasure, stimulation and escape. "It takes the same pathway as our drugs of abuse and pleasure."

"It's an addiction," he said, adding that some people cannot deal with down time or quiet moments. "Without it, we are in withdrawal."

My impression has always been that people who multitask always claim that they are getting so much done, but my observation has been that they tend to get very little done if the tasks that they are doing involve producing something, whether physical or virtual. Multitasking may be more efficient if what you do all day long is talk to people, whether that's meetings, e-mail, or phone. The problem is that at some point you have to produce something. A sales order, a document, a program, a widget. When that point comes, its hard to multitask because you make mistakes, etc.

There are some things which only happen in quiet moments, or after some careful reflection. People who are constantly multitasking and always on don't get to have those moments.